Rivet slug injector

ABSTRACT

An intermittent acting mechanism receiving rivet slugs from the delivery tube of a rivet dispenser for injecting each slug into a spring loaded finger mechanism which, in turn, inserts the slug into a previously drilled hole for a rivet upsetting action by an automatic riveting machine. A photoelectric cell verifys insertion of the rivet slug into the finger mechanism and signals for the next step in the drilling operation. An adapter unit permits rapid and accurate conversion for slugs of different diameters and lengths without extensive alignment and readjustment.

[451 Oct. 24, 1972 11/1963 Klancnik................221/271X 11/1970Spisak.......................221/233 FOREIGN PATENTS OR APPLICATIONS11/1963 Germany...................22l/241 yer and ABSTRACT Anintermittent acting mechanism receiving rivet slugs from the deliverytube of a rivet dispenser for injecting finger mechanism g into apreviously drilled on by an automatic rivet- Primary Examiner-Smauel F.Coleman Attorney-Walter J. Jason, Donald L. R0 Robert 0. Richardson eachslug into a spring loaded which, in turn, inserts the slu hole for arivet upsetting acti ing machine. A photoelectric cell verifys insertionof Inventor: Earl K. Kelly, Lynwood, Calif. Assignee: McDonnell DouglasCorporation Filed: June 29, 1970 Appl. No.: 50,825

Field of Search 221/239, 255

References Cited UNITED STATES PATENTS United States Patent Kelly 1541RIVET SLUG INJECTOR [721 X the rivet slug into the finger mechanism andsignals for the next step in the drilling operation. An adapter unit Xpermits rapid and accurate conversion for slugs of difx ferent diametersand lengths without extensive align- Erickson................22l/241 Xment and readjustmem' Mead ....22l/239 X f Taylor...................221/241 X 2 Claims, '5 Drawing Figures RIVET SLUGINJECTOR BACKGROUND OF PRESENT INVENTION For automatic rivetingmachines, a quantity of rivet slugs are placed in a rivet dispenserwhich, in turn, channels the slugs into a tube in end-to-endrelationship. Each slug is then moved by a rivet slug injector from thisdispenser tube into a finger mechanism which, in turn, inserts the sluginto a previously drilled hole and the riveting action takes place.Since rivets are of various sizes and lengths, adjustments must be madewhen converting from one size to another.

Much non-productive time occurs when rivet slug injectors of presentdesign are used and it is desired to change rivet slug diameters. Trailand error adjustments are presently required by such a conversion andtime losses are attributable to the malfunction of the presentinjectors. In the conversion of a riveting machine to drive rivet slugsof another size, the type of injector now in use must be removed andreplaced with a similar unit of appropriate capacity. The photoelectriccell obstructs access to the injector mechanism and must be removed,replaced and realigned. Alignment of the cell for proper operation iscritical and the conversion also entails bending the rivet slug deliverytube to achieve proper alignment with the alternate injector. Theseadjustments are of a trial and error nature and when not properly madecause a malfunction. This can result in damage, hand operation andfurther loss of time.

In addition to this conversion problem, the present injectors frequentlyfailed to insert the rivet slug into the finger mechanism, in which casethe slug falls to the work surface and the photoelectric interlock haltsthe automatic cycle. The operator must actuate the injector under manualcontrol to insert another slug into the finger mechanism and resume theautomatic mode of operation. An unreliable return spring may fail tocomplete the reciprocating action of the injector mechanism and thecycle may be repeated without the slug in proper position. Repetitivemanual operation is again necessary to pick up the next slug from thedelivery tube.

SUMMARY OF THE PRESENT INVENTION The improved rivet slug injector of thepresent invention provides for interchangeable adapter units to quickly,easily and accurately convert the injector for use from rivets of onediameter to rivets of another diameter. The same basic injector unit maythus remain intact and the conversion problems of previous injectors arethus eliminated. Proper alignment is maintained without trail and erroradjustments and the need to remove and replace the photoelectricinterlock structure. .No dismantling and realignment is necessary. Theinjector has a body to which is fastened a double acting air cylinderwhich extends and retracts a blade between an extension block and springclosed gate. Slugs from a delivery tube drop down onto the adapter andin front of this blade for movement past a photoelectric cell and intothe fingers of a finger mechanism which inserts the slug into a holedrilled on a workpiece. A pointer for the corresponding rivet slugdiameter is permanently attached to each adapter and indicates sluglength adjustment on the appropriate scale stamped on the side of thebody.

. 2 I BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a perspective view ofthe injector with hidden parts in dashed lines and related apparatus inphantom lines;

FIG. 2 is a perspective view of the front portion of the injector;

FIG. 3 is an elevational view;

FIG. 4 is a partial sectional plan view taken along the line showing therelationship of the end of the injector with the finger mechanism; and

FIG. 5 is a perspective view of the replaceable adapter unit with itsassociated blade shown in phantom lines. 1

DETAILED DESCRIPTION OF THE DRAWINGS Referring now to FIG. 1 there isshown a body 10. This body preferably is a rectangular machined part orcasting having a rear portion removed so that a double acting aircylinder 12 may be fitted therein. This cylinder 12 has the usualpneumatic conductors 14 and 16.at either end of the cylinder forlongitudinal movement of a piston rod 18 in the oscillatory actuation of.the injector blade. A vertical slot 20 within the body 10 permits ablade 22 to move with the piston rod 18 in an oscillatory motion shownby the double arrow 24. A clevis 26 interconnects the blade 22 with thepiston'rod 18 for actuation. I

Affixed to the body 10, such as by screws 30, is a tube base 32 having afurther mounting support 34 affixed thereto. A rivet slug delivery tube36 is secured to the tube base 32 such as by welding, for example andhas its end 38 terminating at a point above the lower surface of thetube base 32. Rivet slugs are fed through this delivery tube by agravity feed and dropped down from the delivery tube end 38 onto theupper surface 40 of an adapter unit 42 in front of the leading edge 21of blade 22 when the blade 22 has moved rearwardly of the delivery tube36. In FIG. 1 the blade 22 is shown in an intermediate position afterhaving moved a rivet slug 44 forwardly in its forward stroke. Whenblade22 is in its rearwardmost position, an extension block 46 forwardlyof body 10, and a spring loaded gate 48, with a vertical groove 49therein and pivotally mounted to the front portion of body 10 preventthe rivet 44 from falling off the shelf 40 of the adapter 42 prior tothe forward movement of the blade 22. This extension block 46 formerlywas removable to provide access in replacing the injectors when a changein rivet size was desired. Spring gate 48 is pressed outwardly by theadapter 42 and blade 22 in their forward movement. A captive screw 50 isused in making a' vertical adjustment of the adaptor 42 relative to theblade 22 to accommodate the various lengths of the rivet 44. There areindicia markings 52 on the side of the body 10 and a pointer 54connected to the adapter 42 is used in determining the vertical heightto accommodate the predetermined rivet lengths.

Although not part of the present invention but used in conjunctiontherewith, is an electric eye mechanism that insures that a rivet hasbeen passed by the blade 22 to a spring finger mechanism, not shown.This photoelectric mechanism is shown in phantom lines as consisting ofa light source 56 secured to a support arm 58 attached to a mountingbracket 60 and a photoelectric cell 62 attached to a support arm 64 onbracket 60.

In one embodiment mounting bracket 60 extends rearwardly of tube base 32and is fastened to the top of the injector body 10. The light source 56projects a light onto the cell 62 in the well known manner, and thislight source is interrupted upon the passage of the rivet 44therebetween. This, in turn, actuates appropriate structure toaccomplish the riveting operation. In one embodiment the electric eyesignal starts a drilling operation.

A perspective view of the front portion of the injector is shown in FIG.2. Here is shown piston rod 18 and clevis 26 for attachment to the blade22. The piston and blade move longitudinally through a slot 20 betweenthe outer walls of body 10. Tube base 32 is mounted on the top of bodyportion by means of screws 30. A support 34 interconnects thetube baseto other mounting structure. The rivet slug delivery tube 36 isconnected to the base 32. A leaf spring 68 urges gate 48 inwardly intocontact with the extension block 46 and is pried outwardly upon thepassage of rivet 44 and blade 22in the forward stroke.

The elevational view in FIG. 3 more clearly shows the operation of the'rivetslug injector. As previously explained, the body 10 has a doubleacting air cylinder 12 mounted therein. Tube base 32 is shownmounted onthe top and underneath this base isthe blade 22 fastened by the clevis26 to the piston rod 18 for longitudinal movement under the rivet slugdelivery tube 36. Adapter 42 is fastened to the blade 22 by means of acaptive screw 50, the rotation of which makes a vertical adjustmentbetween the adapter and the blade.

Guide bars 70 permit vertical relative movement while carrying theadapter 42 with the blade 22 in its longitudinal movement. Adapter 42extends forwardly from the blade 22 to provide a shelf 40 upon which therivet 44 is positioned when it drops down from the tube 36 when blade 22is retracted rearwardly of the tube. When forward movement is impartedby the piston rod 18, the leading edge 21 of blade 22 pushes rivet 44from groove 49 forwardly past the springretained gate 48. The adapter 42and pointer 54 are carried with the blade 22. An intermediate positionof the rivet movement is shownby dotted line 72 and its full forwardposition is shown at 74 where it is retained by a spring biased fingermechanism 76. This finger mechanism frictionally retains the rivets inthe position shown by rivet 74 while hammer 78 performs the rivetingoperation. The actuation of the air cylinder 12 to initiate the forwardmovement of the blade 22, in one embodiment, is caused by a limitswitch, not shown, tripped by a horizontal movement of the fingermechanism 76 toward the blade to receive the injected rivet.

As can be seen in the plan view in FIG. 4, the electric eye has itslight source 56 and photoelectric cell 62 between the finger mechanism76 and the end of gate 48 and extension block 46 so that as the blade 22pushes the rivet 44 past the position shown by dotted line 72,appropriate signals are generated so that the riveting operation may bemade after the rivet has been positioned within the fingers at position74. The fingers of this finger mechanism 76 are outwardly urged by therivet slug which is frictionally retained by them until the rivetingoperation has taken place.

The adapter unit is shown in FIG. 5. Here the double acting air cylinder12 appears in phantom lines with the piston rod 18 and the blade 22 thatis interconnected with the piston rod by means of clevis 26 forlongitudinal actuation. The adapter 42 is a rectangular plate positionedforwardly and below the forward edge of the blade and is connectedthereto by guide bars which permit vertical adjustment therebetween. Thevertical adjustment is accomplished by a captive screw 50 whose head isfrictionally retained by a leaf spring lock 82. Upon manual rotation ofthe head 80, the

screw 50 moves the adapter 42 vertically relative tothe from each otherin the thickness of the adapter or in the vertical elevation of thetable 40 with respect to the blade 22. The injector unit thus is asimpler mechanism with greater reliability and in its applicability to avariable operating need where formerly separate devices werenecessary.Interchangeable adapters permit rapid conversion to accept alternateslug diameters without replacing the entire ejectorassembly andrealigning critical parts by a trial and error process.

Having thus described one form of the invention, it is to be understoodthat various modifications will readily occur to one skilled in the artand that it is to be understood that these variations are to beconsidered as art of the present invention.

Iclaim:

l. A rivet'slug injector comprising a body having an open ended verticalslot therein,

a blade longitudinally movable within said slot,

means for actuating said blade,

a rivet slug delivery tube affixed to said body over said slot andadapter to drop rivet slugs therein in upstanding orientation,

said blade having an adapter unit affixed thereto to provide an upperhorizontal surface forwardly of said blade to receive the base ends ofsaid rivet slugs, said adapter unit being movable with said blade andvertically adjustable relative thereto,

said blade being horizontally movable to a first position out ofvertical alignment with said tube with said upper surface beingpositioned thereunder, said blade being horizontally movable under saidtube to prevent further droppage of rivet slugs until said blade returnsto said first position, said blade being horizontally movable under saidtube to a second position where the rivet slug carried thereby may beremoved, and

a spring biased gate closing said open end of said slot when said bladeis in said first position, said gate having a vertical groove along theinner surface thereof into which said rivet slug is positioned upondropping from said delivery tube.

2. A rivet slug injector as in claim 1, said adapter unit beingconnected to said blade through guide bars and a captive screw foradjusting vertical spacing therebetween,

said guide bars fitting into vertical apertures in the top of saidadapter unit and in the bottom of said blade,

said adapter unit having indicating means thereon overlying indicia onsaid body to indicate vertical 5 adjustment of said adapter unit forselected lengths of rivet slugs.

1. A rivet slug injector comprising a body having an open ended verticalslot therein, a blade longitudinally movable within said slot, means foractuating said blade, a rivet slug delivery tube affixed to said bodyover said slot and adapter to drop rivet slugs therein in upstandingorientation, said blade having an adapter unit affixed thereto toprovide an upper horizontal surface forwardly of said blade to receivethe base ends of said rivet slugs, said adapter unit being movable withsaid blade and vertically adjustable relative thereto, said blade beinghorizontally movable to a first position out of vertical alignment withsaid tube with said upper surface being positioned thereunder, saidblade being horizontally movable under said tube to prevent furtherdroppage of rivet slugs until said blade returns to said first position,said blade being horizontally movable under said tube to a secondposition where the rivet slug carried thereby may be removed, and aspring biased gate closing said open end of said slot when said blade isin said first position, said gate having a vertical groove along theinner surface thereof into which said rivet slug is positioned upondropping from said delivery tube.
 2. A rivet slug injector as in claim1, said adapter unit being connected to said blade through guide barsand a captive screw for adjusting vertical spacing therebetween, saidguide bars fitting into vertical apertures in the top of said adapterunit and in the bottom of said blade, said adapter unit havingindicating means thereon overlying indicia on said body to indicatevertical adjustment of said adapter unit for selected lengths of rivetslugs.